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प्रश्न
What is PCR? Explain different steps involved in it.
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उत्तर
Definition: Polymerase Chain Reaction (PCR) is the process of in vitro amplification of gene of interest using a PCR machine.
Mechanism of PCR: At the start of PCR, all the requirements are mixed together in ‘eppendorf tube’ and the following operations are performed sequentially:
Step i: Denaturation
The reaction mixture is heated to a temperature (90–98o C) to separate two strands of desired DNA. This is called denaturation.
Step ii: Annealing
The mixture is allowed to cool (40–60o C) that permits pairing of the primer to the complementary sequences in DNA. This step is called annealing.
Step iii: Primer extension / Polymerization
The temperature (70–75o C) allows thermostable Taq DNA polymerase to use single-stranded DNA as template and adds nucleotides. This is called primer extension. It takes around two minutes duration.
संबंधित प्रश्न
Name the genes responsible for making Bt cotton plants resistant to bollworm attack. How do such plants attain resistance against bollworm attacks? Explain.
Match the Column I (Restriction enzyme) with Column II (Recognition sequence) and select the correct option.
| column I (Restriction Enzyme) | column II (Recognition sequence) | ||
| i. | Alu | P. | 5'---G- ↓-G-A-T-C-C---3' 3'---C-C-T-A-G- -G---5 |
| ii. | BamHI | Q. | 5'--- A-G- ↓ -C-T---3' 3' ---T-C- G-A--- 5' |
| iii. | Eco RI | R. | 5'--G-T-C- ↓ -G-A-C--3' I 3'--C-A-G-t-C-T-G--5' |
| iv. | HindII | S. | 5'---G- ↓ -A-A-T-T-C---3' 3'---C-T-T-A-A- -G---5' |
Polymerase Chain Reaction is made possible by ____________.
The vector Baculovirus is used for gene transfer in ____________.
DNA fingerprinting refers to ______.
Study the following lists and choose the correct match.
| List I | List II |
| A. Vector | (i) Resistant to cotton bollworms |
| B. Downstream processing | (ii) Mobile genetic elements |
| C. Cry II AB | (iii) Controls corn borers |
| D. Transposons | (iv) Ti plasmid |
| (v) Purifying protein in biopharmaceuticals |
The DNA polymerase enzyme used in PCR is obtained from______.
______technique is used for in vitro gene cloning or gene multiplication.
Suneeta is planning an experiment to clone a gene in a vector. So, she has to choose a good cloning vector.
Which one of the vectors shown below should she choose? Justify your answer by giving two reasons.
 |
 |
 |
| Vector A | Vector B | Vector C |
When the phage DNA enters the host bacterium, the host cell protects itself from the viral DNA attacks with the help of ______ enzyme.
